1. Field of the Invention
The present invention relates in general to extrusion techniques and particularly to a method for processing extrudable material for the manufacture of an extrusion product, advantageously a multilayer extrusion product, by an extrusion device, wherein the extrudable material is brought in solid form, preferably as powder or in granular form, and which comprises a central extrusion channel as well as a stator means and a rotor means defining said channel; and also to an extrusion device for processing the extrudable material to produce an extrusion product, advantageously a multilayer extrusion product, into which extrusion device the extrudable material is brought in solid form, preferably as powder or in granular form, said extrusion device comprising a central extrusion channel as well as a stator means and a rotor means defining said channel. The invention relates also to an extrusion product.
2. Background Art
Traditional extrusion methods can principally be divided into extrusion carried out by so-called axial extruders and the one carried out by so-called radial extruders.
As drawbacks concerning the axial extruders, the benefit of which is a good resistance against pressure load, can be mentioned, that especially for the production of rotationally symmetrical and/or multilayer products many axial extruders must be connected to the extrusion head, whereby dispension of the extrudable mass evenly and homogenously at the extrusion head creates a problem, this being hardly possible or even totally impossible, especially when even minor variations or regulations of the extrudable mass flow amounts occur in the processing, and as a result almost without exception an eccentric and unhomogenous extrusion product is obtained.
A drawback in radial extruders, the benefit of which is a rather good adaptability for production of rotationally symmetrical and multilayer products, is a poor resistance against pressure load, so that the device can only be used for low yields. For higher yields the sizes and dimensions substantially increase, whereby the investment costs of a radial extruder become significantly high compared with the advantages gained.
The main object of the present invention is to provide a new method and extrusion device for processing extrudable material and at the same time to combine the benefits of traditional extrusion techniques and to eliminate the drawbacks relating thereto. The goal and the purpose of the present invention is particularly to enable by the improved method and the new device both the manufacture of multilayer products and the increase of yield as well as variation possibilities of the number of layers in the product.